The present invention relates to a phase adjustable pin electronics device for use in IC testers and a phase adjustment method therefor.
FIG. 1 shows the arrangement of a conventional IC tester as disclosed in U.S. Pat. No. 4,497,056. Reference numeral 10 indicates generally an IC tester main device, 20 a pin electronics device, and 30 an IC under test.
The pin electronics device 20 is provided with drivers 21 each providing a test pattern signal for each for channels CH.sub.l to CH.sub.n corresponding to respective terminals of the IC under test 30, and logical comparators 22 each determining whether or not a response out put signal from one of the terminals of the IC under test 30 has a predetermined level at predetermined timing.
The driver 21 and the logical comparator 22 for each channel are connected via a relay 24 to the corresponding terminal of the IC under test 30. Reference numerals 25 and 26 designate variable delay elements for skew adjustment in each channel. The variable delay elements 25 and 26 are provided in each channel for adjusting the phase of a drive pulse D to be applied to the corresponding terminal of the IC under test 30 and the phase of a strobe pulse ST to be applied to the logical comparator 22, thereby putting the phases (hereinafter referred to as skews) of the drive pulses D and the skews of the strobe pulses ST into agreement. The logical comparators 22 each compare the input signal level with a reference voltage at the fall of the strobe pulse ST, and output and hold a logical "1" or "0" until the next comparation is effected depending upon whether the former is higher or lower than the latter.
The pin electronics device 20 further includes a calibrator CAB which has a reference driver 27A and a reference logical comparator 27B which perform a reference operation with respect to the driver 21 and the logical comparator 22 provided for each channel. The reference driver 27A and the reference logical comparator 27B are used to adjust the variable delay elements 25 and 26 in such a manner as described below.